This invention relates generally to terminals for making electrical connections, and more particularly, to a tab terminal.
Dynamoelectric machines such as motors typically include a start winding and a run winding. The start winding is utilized to initiate rotation of the motor rotor. Particularly, the magnetic field generated by the relatively high inductive reactance start winding in a resistance split phase motor may be about 30 degrees out-of-phase (in both a physical sense and a time sense) with respect to the field generated by the relatively lower inductive reactance rim winding. When the run and start windings are energized, the geometric and time phase relationship between magnetic fields generated by the run and start windings, and the magnetization of the rotor, cause the rotor to begin rotating from a standstill condition. Once the rotor has sufficient torque to attain its normal running speed, the start winding is xe2x80x9cswitched outxe2x80x9d of the motor circuit so that the out-of-time phase geometrically spaced magnetic field generated by the start winding does not adversely impact motor operation.
Start and run capacitors sometimes are utilized to change the time phase relationship between the magnetic fields generated by the run and start windings. A start capacitor connected in series circuit with the start winding causes the magnetic field generated by the start winding to be, for example, about 90 degrees (rather than about 30 degrees) out-of-time phase with the run winding field. As compared to a 30 degrees time phase shift, a 90 degrees time phase shift of the start winding magnetic field results in a higher starting torque, which is desirable in some applications.
In addition to run and start capacitors, other externally mounted motor components may include motor protectors and motor start switches. A motor overload protector coupled between the motor windings and the motor power supply, and responsive to such a high current condition, operates to de-energize the motor windings if such a high current condition persists for a predetermined time period. A motor starter switch, sometimes referred to herein as a xe2x80x9cstarterxe2x80x9d, may be employed to control the energization and de-energization of the motor start winding.
By housing a starter switch and protector in one unit, manufacturing costs may be reduced and assembly of at least the starter and protector to a motor may be simplified. Examples of such units are set forth in U.S. Pat. No. 5,729,416, which is assigned to the present assignee. The motor starter and protector unit includes a terminal for making an external connection to ground. The terminal is formed by bending, to about 90 degrees, an extension and folding over portions of such extension. A female connector is then pushed over the terminal to make the connection to ground.
In accordance with the applicable standard, the terminal must have a nominal thickness of {fraction (32/1000)} inch. With the terminal described above, the required thickness is achieved by folding over portions of the extension. The folding operation results in significant wear of the tooling. Particularly, the tooling required for such folding operations generally presses the extension, and during such pressing operations, opposing tool faces are brought into abrupt surface to surface contact. Such operations cause the tooling faces to chip and crack. The tooling faces therefore require frequent machining, or replacement, which increases fabrication costs and time.
Further, with the known terminal, the leading edge of the terminal is sharp and sometimes digs into the locking mechanism on the mating connector, which increases the difficulty in assembling the connector to the terminal. Also, in some applications, the assembly of the connector over the terminal is a xe2x80x9cblindxe2x80x9d operation, i.e., the operator cannot view the terminal as the connector is slid thereover.
It would be desirable to provide a terminal that satisfies the applicable thickness requirement, yet also can be fabricated without causing excessive tool wear. It also would be desirable to provide such a terminal that is easily coupled to a connector.
These and other objects may be attained by a terminal including a connector plate having raised, or embossed, surfaces arranged so as to satisfy the applicable thickness requirement, and which also can be fabricated without use of the folding operation required in connection with the terminal described above.
More particularly, and in one embodiment, the connector plate includes a fluted section having raised surfaces. The raised surfaces provide that the terminal has the thickness required by the applicable standard, without requiring that the terminal be folded over. By eliminating the folding operation while still providing the required thickness, the terminal can be fabricated with less tool wear. In addition, and since the material is not folded over at the leading edge of the plate, the thickness of the terminal at the leading edge is reduced as compared to the thickness of the above described terminal. Reducing the thickness at the plate leading edge provides that a mating connector can be more easily engaged and slid thereover.
Further, the leading edge of the plate includes tapered sections, and a slot extends from and is open at the plate leading edge. The tapered sections facilitate alignment of the connector plate with the female connector, and pushing the connector thereover. As the connector is pushed over the terminal, the connector locking mechanism slides through the slot. As the connector is further pushed over the terminal, the locking mechanism easily slides along a ramp formed by one of the raised surfaces and into a retaining hole in the terminal.
The above described terminal satisfies the applicable thickness and connector locking requirements, yet also can be fabricated without causing excessive tool wear. In addition, the terminal is easily coupled to a connector.